An automatic analyzer for automatically executing the analysis of a sample is provided with a sampling device for collecting a sample with a probe. A sampling device is a device for automatically executing an operation in which, when an analyzer installs a sample container containing a sample such as blood in a prescribed location, the sample container is transported to a prescribed aspiration position, and a probe for sample aspiration aspirates the sample in the sample container at the aspiration position and dispenses the sample at a dispensing position provided at another location.
In order to prevent the drying of the sample housed in the sample container, the upper surface of the sample container installed in the sampling machine is typically sealed by a cap consisting of an elastic member or the like. Therefore, a conventional, typical sampling machine was configured so that, when aspirating a sample in the sample container with a probe, the probe is lowered from above the sample container and is made to penetrate through the cap on the upper surface so that the tip of the probe is inserted into the sample container. However, the shavings of the cap generated when the cap is penetrated by the probe sometimes clogged the aspiration/expelling port of the probe tip.
In order to prevent the clogging of the aspiration/expelling port of the probe by the shavings of the cap, the aspiration/expelling port may be provided on the side surface of the tip part of the probe, but this makes it impossible to aspirate the entire sample housed in the sample container with the probe, which leads to the problem that the dead volume of the sample becomes large. In addition, when the aspiration/expelling port is provided on the side surface of the tip part of the probe, the drainage becomes poor, which leads to the problem that the minimum dispensing amount becomes large.
Therefore, the idea of providing the device with a piercer for penetrating and piercing the cap of the sample container separate from the probe for aspirating/expelling the sample has been proposed and implemented (see Patent Document 1). A typical piercer is a member having a cylindrical shape with a pointed tip. The piercer is lowered from above the cap so as to penetrate the cap and form a hole of a size that allows the probe to pass into the penetrated region.
In a sampling device equipped with a piercer, when a sample container to be sampled is placed at a prescribed sampling position, the piercer is first lowered from above the sample container and stopped after penetrating the cap sealing the supper surface of the sample container. A probe is then lowered from above the piercer penetrating the cap and so as to enter the sample container through a hole formed in the cap through the inside of the cylindrical piercer, and the sample in the sample container is aspirated from the tip of the probe.
When blood is collected using a vacuum blood collection tube as a sample container, a small amount of blood may remain on the cap after the probe aspirating the blood is pulled out of the cap of the blood collection tube. When a perforation operation is performed on the blood collection tube with a piercer, blood adheres to the piercer. In addition, when perforation is once again performed on a blood collection tube that has been perforated once before due to a reexamination or the like, blood as well as fine shavings of the rubber cap adhere to and contaminate the inside surface or outside surface of the piercer. In order to prevent contamination between samples due to such contamination of the piercer, it is preferable to be able to wash the piercer.